The vehicle towing industry requires lifting mechanisms for safely lifting heavy objects, such as disabled vehicles. These lifting mechanisms are typically attached to tow trucks. One required function of a tow truck's lifting mechanism is to lift an end of a vehicle and safely enable its transport without damage to the vehicle. Safely lifting a heavy object requires a mechanism that includes simple safety features. Such safety features should be easily or automatically activated to help eliminate the potential of injury or damage.
Most conventional tow truck lifting mechanisms rely on hydraulic actuators to supply the significant force required to lift the disabled vehicle. Hydraulic actuators, though ideally suited for such heavy duty use, can fail. Hydraulic actuators rely on a pressurized fluid to operate and often to maintain a desired position. An interruption or loss of hydraulic fluid pressure poses a serious safety hazard. Significant numbers of tow truck operators are injured on the job, by events directly stemming from a sudden failure of the hydraulic system. Once the hydraulic system fails, the lifting mechanism will suddenly travel to a resting position, often allowing the vehicle to fall to the ground, potentially harming anything in its path. Therefore, a need exists for an apparatus that helps to minimize the potential hazards encountered in failures of hydraulic systems that are utilized in lifting mechanisms.
Tow trucks are typically retrofitted with lift mechanisms. A lift mechanism manufacturer receives a tow truck at its factory, where the lift mechanism is then added. Ideally, a safety apparatus incorporated into such a retrofit lift mechanism would need to be simple and economical. An additional need exists for a safety apparatus that easily accommodates the lifting mechanism of a tow truck that is especially suited for a retrofit installation.
Other industries, where heavy objects are routinely lifted, would also benefit from an apparatus that provides safety for lifting mechanisms. Additionally, other lifting actuator types than those utilizing hydraulics, could also benefit from an apparatus that reduces the potential of damage or injury that can result from the failure of the lifting actuator.